1. Field of the Invention
The present invention relates to a sensor equipped wheel support bearing assembly having a load sensor built therein for detecting a load imposed on a bearing unit for a vehicle wheel.
2. Description of Related Art
As a technique for detecting a load acting on each of vehicle wheels, a sensor equipped wheel support bearing assembly has been suggested (in for example, the Patent Document 1 listed below), in which a strain occurring in a flange outer diametric surface of an outer ring of the wheel support bearing assembly, which works as a stationary ring, is detected. Another sensor equipped wheel support bearing assembly is also suggested (in, for example, the Patent Document 2 listed below), in which as shown in FIG. 66, a strain gauge 51 is pasted to an outer ring 50 of the wheel support bearing assembly for detecting the strain.
A further sensor equipped wheel support bearing assembly is suggested (in, for example, the Patent Document 3 listed below), in which a sensor unit made up of a strain generating member and a strain sensor fitted to the strain generating member is fitted to an inner diametric surface of an outer member of the bearing, which works as a stationary ring, and the strain generating member has a contact fixing segment at at least two locations relative to the outer member and a cutout at at least one location between the neighboring contact fixing segments, with the strain sensor arranged on this cutout.
According to the sensor equipped wheel support bearing assembly disclosed in the Patent Document 3, supra, when a load acts on a rotatable ring during the travel of an automotive vehicle, such load is transmitted to the stationary ring through rolling elements so that the stationary ring deforms, and therefore, such deformation brings about a strain in the sensor unit. The strain sensor provided in the sensor unit detects such strain occurring in the sensor unit. If relations between the strain and the load are determined beforehand by means of a series of experiments and/or simulations, the load or the like acting on the vehicle wheel can be detected from an output of the strain sensor.